Carbon-carbon type composite materials (with carbon fiber reinforcement and carbon matrix) have proved to react well to various applications involving high thermomechanical stresses, such as in tuyere elements for rocket motors, aircraft brake discs, etc.
In an attempt to further improve the properties of composite materials, particularly at high temperature, ceramic materials have been used for the fibrous reinforcement and for the matrix, instead of carbon which has been found to have a limited mechanical resistance and an inadequate resistance to oxidation when exposed for prolonged periods in an oxidizing medium at high temperature.
It is generally well-known that in composite materials with fibrous reinforcement, the properties of the fibers-matrix interface have a great influence on the mechanical properties of the material.
In the case of composite materials with ceramic matrix, it has been found that a satisfactory behavior could be obtained, particularly as regards shocks and crack propagation, and in spite of the ceramic nature of the matrix, by forming on the fibers a thin intermediate coating of for example pyrolytic carbon deposited by chemical vapor deposition, or of boron nitride, before the infiltration of the ceramic material of the matrix.